This disclosure relates generally to systems for the preparation of printed items. More particularly, the present disclosure relates to systems for verifying the integrity of print products.
Many print jobs prepared by modern print shops must be printed as multiple print runs due to differing specifications for each of the print runs. For example, the print job may require the use of different paper stocks for the different print run, or that portions of the print job be printed in black and white while other portions of the print job be printed in color. Completion of the print job therefore requires that the printed pages from the several print runs must be separated from printed pages for other print runs, matching those printed pages to the print job, collating the printed pages and packaging the print job for delivery to the customer.
It should be appreciated that the potential for damage to a print run can occur at any point of the printing process, including during binding and in packaging or fulfillment operations. Therefore, multiple inspection/verification points are required to ensure that print run quality is maintained.
In addition, the tasks recited above may each include a number of sub-tasks. For example, each print run requires supplying a set of printing instructions intended for printing a particular portion of the print job document to the printer device and then printing the document portion in accordance with the supplied sets of printing instructions. A number of mutually different processing instructions may be supplied to a station of an apparatus for assembling print jobs, which processing instructions are each associated with particular sets of the sets of printing instructions. Accordingly, the possibility exists that due to errors in the printing of the document portions or in the transport of printed document portions from the printer to the assembly station, an assembled document may include one or more printed document portions associated with another document. Such errors can occur, for instance, in that a document jams or in that a double sheet is supplied to the printer.
As a result of such errors, it is possible, for instance, that a set of personalized documents lacks a last document, which is then included in the next set, intended for a different addressee. It is also possible, for instance, that a bank statement is added to a letter which is addressed to a person other than the person to whose bank account the statement relates. It will be clear that these are extremely undesired consequences. In this connection, it is particularly disadvantageous that an error may have an effect on the assembly of subsequent postal items without this being noticed
In one conventional method of quality control, document portions are provided with special marks, such as a glyph or barcode, which may be read by an optical scanning device. Although the special marks are relatively small, it is necessary, in determining the lay-out of the documents, to leave some space clear for the special marks, which requires additional coordination. Each time a quality control is performed on a document portion, the special marks are read and compared to a listing of the special marks associated with the document to ensure that all the document is complete and does not include any document portions not associated with the document. Since the special marks can only be read by optical scanning devices, each page of the document portion having special marks must be scanned by such a device, resulting in excessive cycle time.